Synthetic filament



March 4 3958' A. s. SMITH 59H0 SYNTHETIC FILAMENT Filed May 11, 1954 2 sheets-sheet 1 Armwswh VEN TOR.

AT1-animen' March 4, 1958 A. s.` SMITH zm@ SYNTHETIC FILAMENT Filed May 11, 1954y 2 sheets-sheet 2 sscr/o/vofSP/NA/Efeff snow/NG ONE u@Amr/cf F-g5 PRIOR ART Affzwssm/i INVENTOR.

l Azz-cangas' 2,825,120 Patented Mar. 4, 1958 United States Patent-Ofice 2,825,120 e SYNTHETIC lIILAlVlEll'l Arthur S. Smith, Kingsport, Tenn., assigner. to Eastman Kodak Company,-Roches'ter,`N. Y., a corporation of New Jersey Application May `11, 1954, Serial No. 428,890 2 Claims. (Cl. 2S-82) This invention relates to the preparation of -synthetic `-filaments and fibers of increased luster, stiffness and in- `creased bulk. More particularly this invention .relates -to improved dryV `spinning methods and apparatus for producing from cellulose ester spinning solutions fila- Iments and fibers of an H-shaped cross-section havingsuch 2desirable characteristics. [Furthermore this invention also vl'relates' to fabrics and other'arti'cles of manufacture 'made of, "orcontaining such H-shapedcross-section .filaments "and fibers.

*Heretofore,"various processesa'nd apparatus'h'ave been fprovided 'for the production of synthetic filaments and fibers Vof Avarious `cross-sections. l known cross-sections fall within one. or two classifica- `tions Suchas relatively narrow 'and rectangular crosssections, or round or round-like cross-sections'which'include'filaments ofv round and Afiat sides, cloverleafconfigurations and other `related variations produced by yphysically deforming the filament, after it has assumed Iitsnormal shape, as it issues from thespinning cabinet. flypical methods and apparatus for dry'spinningsol'utions'intonsynthetic fibers vare disclosed in U.S. yPatents .2,000,047'and 2,000,048 of'May 7, 1935, to H. G.Stone. .Thesepatents'describe methods including the forcing of a heated cellulose ester spinning solution through a" spinnerette V.having a plurality of separated round orifices and vinto a drying chamber containing an evaporation atfmosphere maintained at a suitable-drying temperature. f By such controlled conditions filamentscan beconsistentlyformed of approximately round or clover-leaf crosssection as contrastedto the filaments previouslyproduced -of elliptical shape.

Also, asshown-in U. S. Patent 1,695,45`5'of Decemf-ber 18, y1928,-by drawing the filaments from'thefround orifice spinnerette in a direction other than perpendicu- .lar to-the yhorizontal face of the spinnerette, filaments having a more or less fiattened cross-section are lproduced. It is also known that slight variations from the round cross-section canr be caused by adjusting the particular evaporating conditions under whichV theifilainents vare dried in the spinning cabinet. A suitable selection Vof these conditions will permit the production, from spin- -nerettes having round orifices, of filaments witheither -a smooth or an unsymmetrical, irregular surface.

'In U. S. Patent 1,773,969 of August'26, 1930,`the' tech- "nique lof the extrusion of filament forming solutions through circular orifices into evaporative atmospheres' is also discussed. As described therein'it issuggestedlhat the outer layer of the stream of cellulosic material which is initially circular in cross-section as it issues through the spinnerette orifices hardens or solidifies first forming a skin that is tougher and less fluid than the interior.

-After this initial hardeningvof theout'er 'surfaceftlieinterior ofthefilam'ent is precipitated or dried `.and-th'ereby shrinks while the '.'outerllayer hinber-hardened. ,The

outershell-of-'thelfilament being ltougher and more determined'in shape than the interior, the contraction of the volume of the interior causes the outer film: or layer to Acollapse-.and toassume a'very irregular cross-section 'f ivhichfissin the `'.formlof a figure of many indentationsl.: of varyingfsizes and shapes andewhich vis, oftenquiteffiat. Beca'seof thelfirregularity 'ofshape `and fiatnessffofithe f cross-section of such filaments, their covering powerftheir Generally these well- .can .be constituted .by straight .or .curved boundary. lines. However, .the `filaments .producedby .extruding cellulose ester filament forming- :solutions .through .isuch orifices .have more .or less: cross-.sections .characterizedby .rounded surfaces.

`As .described .in.Hickey yPatent 2,373,892.0f April f1.7,

1945; I-.beam .type crossfsection filaments :or fibersy havvinga high ,degree .of resiliency=and crushresistancemay be produced by-extruding a suitablecellulose :estenso- .lution .through a spinnerette .having .rectangular orifices,

the ratio of the length to the width of .each rectangular rorifice .being/between y1.35 .and 1.65.. Fibersmadeafrom such I-beam filaments are .particularly .useful-.for manu- .facturingcarpet materials, aswell as,.fort.the.manufac Ature .of irugging..and Aother ,pilezfabrics However, the .endsoLthe/Ibeam ,are vof a `round shape anddo vnot .ex-

tend substantiallyfabove Vthe fiat :sectionof .the Ifbeam. An object, therefore, of thev present invention v.is .to

provide asprocess for ,preparing lfilaments. and. fibersV with an increased lbfulk-and .stilfnessas comparedtoabove .discussed :.priorartffibers ofequivalent denier. and chemical composition.

LAnother objectot this inventionisto .provide a-proc .ess.for preparin'gffilamentsfand fibers lof. increased .surface area as -compared-tothe. above .Ldiscussedrfibers .known heretofore in this art.

. Stilltanother object ofthis invention. is to .providefsyny theticlamentsand:fibers .of Hfshaped cross-.sectionrof the nature. hereinafter described.

Axfurther .object of .this tinvention. is .thexpreparation vof the desired filaments and fibers from spinneretteorifces ofa simplified design that can be-.easily andxaccurately.manufactl.lred.Y

Yet. another object of -this..inventionfis.to provide a :spinnerette having .extrusion .orifices therein Iof square shapes.

Another objectis to provide staple fibers made ..from

. apluralityof filaments .having H.shaped rcross-sections.

Againv another object. is. to provide new and...novel fabrics containing such Hshaped.cross-sectionlaments or staple fibers.

Still another object is.to .provideanovel:fillingrnaterial Yof increased resistance-,tormatting y.which is,.suit

able to employ in pillows andthelike.

Yet another objectofthisinvention is to, .provide fibers adaptable for use inV manufacturing.cigaretterfilters Other .objects will appear hereinafter.

In accordance with .thepresent:.inventionxthese` and other objects maybe attained. ,by.forcing. a suitable.. spin .ning solution through aspinnerette havingagplurality of square shaped filament., forming..A orifices therein. and

. drying theresulting filaments.. in a spinning-.acabinetunifilameitsraslhey leave the square orifices temporarily 4.assume-fa lsquare.cross-sectional shape. However, in ac ycordance withA vmy invention, by careful control of the Aextrusion rateithe.drafting rate and drying temperatures,

ltherewill be. a change in the filament cross-sections from :zsquare toganV H-'shaped cross-section. .x1-anges of pera'tiongas suggested above, and as devscribed in. djetailfurther on in this specification, the H- 70. .1 cross sectionl willjbe; substantially uniform for each ot Under preferred thesimultaneously extruded filaments.

In general the spinnerette having the square orifices may be employed with any suitable spinning cabinet such as, for example, one of the general kind `described herein. The H-shaped cross-section filaments, however,

i connected a spinnerette 13which in accordance with this invention has a plurality of orifices 14 therein which are of square shape. The face of this novel type of spinnerette with the square orifices 14 therein is shown can be prepared in accordance with our invention within in the greatly enlarged view of Figure 2. The candle a satisfactory range of spinning, drafting and solution iter may be uniformly heated by means of heating conditions as is described hereinafter. coils, not shown, which are positioned so as to surround Another interesting feature of my invention is the dis candle filter 12, and through which coils may be circovery that filaments produced in accordance with my culatcd any appropriate heat exchange medium such as invention through square orifices have a more perfect water maintained at the desired temperature- H-shaped cross-section than is obtainable when a spin- Spinning solution of composition described hereinafter ncrette having H-shaped cross-section orifices is cmis supplied from conduit 16 through valve 17 to pump ployed. In fact in the latter case the laments'gen- 18 which forces the solution at the desired rate tothe erally fall within the above named prior art classifications candle filter unit 12, thence to spinnerettcl from which and are of a distorted rounded configuration and of l5 it is initially extruded through the square orifices -14' in non-uniform cross-section. They exhibit few of the dethe GTIH 0f Square fllamelltS 25- t sirable properties possessed by my novel Hshaped cross- The filaments 25 pass downwardly in the cabinet 11 section filaments. while progressively losing solvent by evaporation until, The increased stiffness of fibers made from H-shaped in a substantially solidified and dried condition they cross-section filaments as contrasted with fibers made of 2O leave the Cabinet 11 and P2155 around gOdCl T011 20, Which filaments of various round or round-like cross-sections iS positioned below the lower end of the spinning cabinet heretofore known in this art appears due to the intermesh- 11, godet roll 2G is driven at a uniform speed by means, ing of the extensions of the H of the individual filaments not shown,V to give the desired draft to the filaments 25. in the filament bundle so that each is reinforced by anl From godet roll 20 the filaments pass over the usual other adjacent filament. t guide rolls v21 and are finally wound onto a bobbin 22 The increased bulk of fibers made of H-shapedtcrossafter an appropriate twist has been imparted thereto, by section filaments depends on the resistance of the H-secmeans not shown. tion filaments to compressive forces when formed into To facilitate drying of solvent from the filaments durfibers or yarn. ing their travel through the cabinet, heated air is sup- Theypresent invention will be further understood by plied to the cabinet 1i by means or' inlet conduits 23 reference to the following detailed description in which and 24 positioned respectiveiy adjacent the lower and several examples `of my invention are given and to the upper ends thereof, the air passing through the cabinet related drawings in which: t and emerging `through outlet conduit 26 positioned at a Figure 1 is a schematic elevational view, partly in secsubstantial distance below spinnerette 13, as illustrated. tion showing a spinnerette which has square filament The change of the cross-section of the filaments while forming orifices positioned in a suitable dry spinning in the cabinet from an initial square cross-section shape cabinet which is equipped with suitable auxiliary apto the desired H-cross section shape is schematically paratus; illustrated in Figure 3; As shown at 2S the filaments Fig. 2 is a view of the face of a spinnerette showing a have just been formed by the square orifices and are plurality of filament forming orifices of square shape; 40 substantially of a square cross-section. Further on, in

Fig. 3 is a greatly enlarged representation of the spinf the downward progress of the filaments under the conning solution coming out of the square orifices of the trolled condition of drafting and drying, they have spinnerette and forming into the H-shaped cross-section changed to the desired H-cross section filaments 25H filaments; which are depicted greatly magnified in Figure 4. The Fig. 4 is a reproduction of an actual photomicrograph 4:3 various conditions of operation are described in more showing the cross-section of several H-shaped filaments detail in the following paragraphs. of the present invention; and My process is described in further detail in the follow- Fig. 5 is a reproduction of an actual photomicrograph ing examples. showing in cross-section several filaments made by em- EXAMPLE 1 ploying a spinnerette having round orifices in accordance with ar prior art method. A spinning solution consisting of 26.5% cellulose acc- The similar parts in the several figures are identified tate, 1.25% titanium dioxide, based on the weight of thc by the same numerals, cellulose acetate, 1.75% water and the remainder being Referring to Figure 1 there is shown schematically the solvent, acctone'was spun into I'iehapcd cross-section a side elevation view, partly in section, of a spinning filaments of 55 denier using the apparatus and its gencabinet 11 and its associated apparatus by which the Y eral operation as described above in connection with novel H-shaped synthetic filaments and fibers of the Figure l. The spinnerette had 13 square orifices therein. instant invention may be manufactured. Mounted at the The conditions of operation are shown in Table I where top of the cabinet is a candle filter unit. 12 to which is they are identified as No. l.

Table I Num- Extru- Candle Extru- Top al Bottom Dimension Denier ber tilasion filter sion Topafr Bottom inlet,` air of one side No. per ments speed, temp temp tiow air ow temp inlet of square Draft strand per M/M "C C C.F.M C. F. M. C temp. spinnerette strand C orifice 55 13 500 65 50o 50o 70 ss o. 0er 1. 10 19 m0 62 500 500 70 85 0.061 1.10 as 500 65 soo S00 70 85 0.067 1 1o 150 7 211 65 non aco 60 90 o. 155 1. 22 55 36 50o 68 500 500 eo 85 0.047 75 49 500 58 500 500 6o S5 o 047 1. 43 300 7 100 es 1,500 1.5110` 60 90 0.220 1.08

j In this table'the ar fiowin cubic feet per minute is Ac"a"l'culate d` for one liid'ereds'pinning cabinets; The ligf' l'le's under the* spinnerette orifice column represent one side of thev square. Theextrusion speed in meters Aper minute represents theV rate at which the spinning solu-J tion is forced out of the spinner'etterf This, in cooperation with the draft rate enables theiilaments'tok change from the initialsqu'are cross-section tok the H-'cross-sect-ionvfilaments wound onto andA ofi the godet` roll is extruded' through any one of the plurality off orifices in the spinnerette employedn the spinning operation, the velocities beingfexpressed in the same units ofdistance per" unit time. For example, if the flarnents'arerwound, up at thel godetroll at the same linear velocity that the spinning, solution is extruded from the spinnerette, the draft is 1.0, thus signifying that the linear speed of wind-up isi 100% of the extrusion speed. Similarly, if the filaments are wound up or withdrawn fromthe cabinet at the' godet.

roll at alinear speed 50% greater than thespeed of ex-.. trusion, the draft is 1.5, and'so on.

O-ther. columns of Table I are more or lessvselfsexplan.-V atorywhen considered, in. connection with Figure lof: the drawings and the related description.`

EXAMPLE 2 TheA cellulose acetate spinning solutionof Example 1 was spun into H-shaped cross-section filamentsV of 75 denier-per strand using they apparatus and its general opg erationas previously described. The spinnerette had19 square orifices. The conditions ofl operation are shown in Table I where they are identified as No. 2.

EXAMPLEv 3 Thecellulose acetate spinning solution of. Example lwas spun into H-shaped cross-sectionfilaments ofV 150 denier per strand. The spinnerette had 38 square orifices. The above described spinning equipment was used with the operating conditions shown as No. 3 in Table I.

EXAMPLE 4- A different spinning solution consisting yof 30.0% ce1- lulose acetate, 1.75% water and the remainder being acetone. solvent was spun into H-shaped cross-section filaments of 150 denier. The spinnerette had 7 square orifices. The above-described spinning equipment was used with the Operating conditions shown as No. 4 in Table I.

EXAMPLE 5 Another spinning solution consisting of 26.5 cellulose acetate, 0.6%v titanium dioxide pigment, based on the Weight -of the cellulose acetate, 1.75% water and the remainder being acetone solvent was spun into H-sllaped cross-section filaments of 55 denier. Thesame spinning equipment was employed with the operating conditions shown as No. 5 in Table` I. l

EXAMPLE-l 6 AKV spinning solution of the composition shown in-Ex ample 5 was spun into H-shaped cross-section filaments of 75 denier. The same spinning equipment was employed with the operating conditions shown as No. 6 in Table I.

EXAMPLE 7 A spinning solution consisting of 26.5% cellulose acetate, 1.75 water, the remainder being acetone was spun into tet-shaped cross-section filaments of 300 denier. The

--6 spinning equipment hereindescribed was employed using aspin'ne'r'etfe having 7's'q`u`are orifices. Conditionsfoperation are shown as No. 7 inTable I.

I have foundthat uniformly H-shaped cross-section filaments can be prepared under a relatively wide rang'el of Aspinning andv dope conditions. A primary requisite for optimum H-shaped cross-sectionv yarn is that vthe spinning draft should be above 1.0 and preferably above.` 11.2. Howeversomewhat deformed H-shapedV cross-section filaments may be obtained. usingI lower spinning!V drafts of 0.7 to 1.0. But asindicatedabove for purposes'- of attaining uniformity ofcross-section a draft above 1.0 is preferable.

The temperatures lis'tedwinr Table I are temperatures used to produce a quality product with a particular cel,

iulose ester-acetone solution. These temperatures are not too critical' and v may vary over a substantial range. Changes in cellulose esters and cellulose ester to acetone rati-Osmay require some alterations or changes inthese temperatures: i

While particular emphasis has been made to preparing? H-shaped cross-section filamentsv from cellulose acetate, my process'will also operate satisfactorily with the' single. and mixed organic acid esters such as those containing 2 to 4 carbon atoms.

I have also found that my spinning process employing spinnerettesvv having square orifices operates very well ov'era- 'range of vdeniers per filament of 1.5 to 43, although-` higher' deniertilaments can be satisfactorily made by. our invention.. v

Tliat the bulk of the H`shaped cross-section fiber, bev` cause? of its particular cross-sectional shape and increased surface area, is greater than the clover-leaf `or regularcross-sec'tion fiber of equivalent denier is shown clearly.y in the following Table II where comparisons of equivaf.

` lent samples of-regular and H-shaped -cross-sectionyarn".

madefrom the same-spinning. compositions are set forth."y Table II BULK TESTS 0N REGULAR AND H-CRoSs-SECTION.. f

CONTINUOUS FILAMENT YARNS Specific Percent. Yarn Bulk factor. volume difference cu. inJlb.'

Regular 55/36/.3 155.2 32. 7 13. 4` H 55 3 .3 175:5 37.1 -...4 Regular 150/381.3 154.1 32.4 9. 9` H 150 38/.3 168. 5 35. 6 Regu lr 300/7 158.0 33.2 14 7 H 300/7/.3.. 180.5 38.1

lnvTable II the. numerical expressions 55/13/.3 and' the like represent continuous filament yarn in terms ofv total denier, filament count, and twist. For example;l 55/ 13/ .3 designates a continuous filament yarn having a total denier .of 55 made up of 13 filamentsandhaving 0.3 turn per inch of twist. The denier per| ilamentof such a yarn is the total denier divided by the number of filaments. In this example 55 divided by 13 equals approximately 4 denier per filament; f

The.V data in Table II are determined by a test', which; has been developed in which yarn is Wound under a specified tension until it fills a spool of a known volume.. The amount of yarn required to' fill this volumey isl weighed. From this weight the Bulk Factor and Specific Vol-A ume are calculated. The Bulk Factor is calculated by the following formula: l (Volume of spoolXdensity of'bers-rweight of'yarn to fill spool) =bulk factor This formula expresses the bulk as a percentage ratio of the space occupied by the yarn to the space which would Table IIVI BULK TESTS ON REGULAR AND H CROSS-SECTIONV STAPLE FIBERS Percent Yarn difference Regular 20/1, 2 D/F, 2" HR 20/1, 2 DIF, 2"

H 20/1, 3 D Regular 12 1. 5 D/F, 2 H 12/1, 5 D/F, 2

In Table III the staple fiber yarns are designated by their cotton count and their ply. For example, 20/ 1 designates a staple fiber yarn made up of a single end, which is 20s cotton count. This table also shows the denier per filament (2 d./f.) etc. and the staple length of the fibers (2") etc., from which the `staple yarns are spun. The bulk factor and specific volume are determined as described above in connection with Table I1. It will be evident that with samples` of yarn of the same composition, denier and length and varying only in crosssection, i. e. between regular and H section,rthat the` H section staple has from 20.0 to 33.2 more bulk.

The luster of the H-shaped cross-section yarn is appreciably greater than that of the Vregular or clover-leaf cross-section of equivalent denier and composition. Lus-` ter is measured by meansof a photo-'electric cell. The filaments are wound in a parallel manner around a fiat piece of cardboard or other similar fiat surface. Light refiected off these panels to the photo-electric cell imparts a potential which is translated into a numerical luster level. of filaments record 0.77 volt whereas the H cross-section filaments of the same denier record 0.80 volt.Y

EXAMPLE 8 Staple fibers made from H shaped cross-section cellulose acetate yarn were employed as a filling material in a pillow. Because of their bulk they were found to be satisfactory for this purpose. A similar sized pillow containing the same weight of cellulose acetate staple fibers of equivalent denier of regular cross-section evidenced less bulk and did not resist matting under pressure.

EXAMPLE 9 On comparative tests the clover-leaf panel assenso cross sectional area. By this method it was determined that H-section filaments are approximately 48% stiffer than `normal `filaments of `equal size. Furthermore, it was found that when a plurality of H-shaped filaments are collected in a bundle as inta yarn strand or ina batting a greatly increased resilience or stiffness is noted which is more thangwould be expected from the increase in stiffness of individual fibers. This effect is attributed to the interlockingor tongue and groove mingling of the legs of the H-flaments making up the mass of fibers. This interlocking of fibers causes much greater resistance to interfiber slippage than can be obtained in a bundle of normal filaments. Thus the aggregate stiffnessl of a bundle of H filaments is much greater than the sum of the stiftnesses of the individual fibers.

The inherent properties of cellulose acetate fibers of the H-shaped cross-section are such that they offer r1u merous desirable properties in both woven and knitted fabrics. In such fabrics as ninons, marquisettes, and voiles, the H-shaped section fibers produce fabrics having desirable crispness and stiffness which are usually obtained only by special processing techniques or by special finishing. In fiat fabrics, such as tafietas, twills, and satins, the increased bulk of the H shaped fibers produce fabrics having greater cover and thickness for a given weight of material. On the other hand there is the possibility of using less material to produce fabrics of the same coverand thickness thereby decreasing the cost. Yarns having an H crosssection produce fabrics with less tendency for the yarns to slip resulting in higher seam strength. This characteristic is particularly important in certain fabrics, for example, satins and twills. Loom finished taffetas have a crisper feel when made from H section yarns.

Knitted fabrics from yarns with H-shaped sections exhibit increasedY body and hand which make them more desirable for certain uses such as sport shirts, mens ties, and dress goods. Yarns'spun from staple fibers of H- cross section exhibit increase in bulky and stiffness as do the filament yarns. In addition, fabrics from these yarns have a wool-like feel or hand. In all of the fabrics which have been produced from cellulose acetate fibers of the H-shaped cross-section fabric properties have been obtained which are desirable and which are not obtained in cellulose acetate fibers of regular cross-section.

I claim:

1. A cellulose organic acid ester filament having an H cross-section, the verticals of the H being substantially uniform and of a length substantially equal to the length of the horizontal of the H plus twice the width of a vertical.

2. A cellulose acetate filament having an H crosssection, the verticals of the H being substantially uniform and of a length substantially equal to the length of the horizontal of the H plus twice the width of a vertical.

References Cited in the file of this patent UNITED STATES PATENTS 2,152,826 Spencer Apr. 4, 1939 2,313,296V Lamesch Mar. 9, 1943 2,373,892 Hickey Apr. 17, 1945 2,434,533 Wurtzburger Jan. 13, 1948 2,588,583 Small et al Mar. ll, 1952 2,588,584 Small Mar. 1l, 1952 2,673,368 Denyes Mar. 30, 1954 2,677,184 Webb May 4, 1954 

1. A CELLULOSE ORGANIC ACID ESTER FILAMENT HAVING AN H CROSS-SECTION, THE VERTICALS OF THE H BEING SUBSTANTIALLY UNIFORM AND OF THE LENGTH SUBSTANTIALLY EQUAL TO THE LENGTH OF THE HORIZONTAL OF THE H PLUS TWICE THE WIDTH OF A VERTICAL. 